* Both sides voice hope ceasefire could be step to permanent peace
* Talks start day late after government tried to invite new groups
* Malian army and Tuareg rebels clashed in recent days
* Army officials say France blocking advance on Kidal
Mali's government and Tuareg separatist rebels began talks on Saturday that both sides said they hoped would lead to a ceasefire ahead of national elections next month and pave the way for a permanent peace deal.
The talks in the capital of neighbouring Burkina Faso, due to conclude on Monday, follow the first fighting in months between Mali's army and the MNLA rebels this week as government forces advanced toward the Tuaregs' last stronghold of Kidal in the remote northeast.
France launched a massive military campaign in January which broke al Qaeda-linked Islamist fighters' control over the northern two-thirds of Mali and allowed the Tuaregs to regain control of their traditional fiefdom of Kidal.
Paris, which is handing over to a U.N. peacekeeping mission due in Mali next month, has pushed hard for elections to go ahead on July 28 to seal a democratic transition from a military coup last year, triggered by the Tuareg uprising.
The immediate goal of the talks is to agree a ceasefire and establish conditions for Mali's government and armed forces to return to Kidal before the presidential vote.
Burkina Faso President Blaise Compaore, who is mediating the talks, has proposed that both sides agree on a method for monitoring the implementation of any deal and on post-election negotiations to achieve lasting peace in northern Mali.
Mali's Tuareg community has for decades demanded greater political autonomy from the southern capital Bamako and more spending on development for the impoverished region, which they call Azawad.
"This meeting raises great hope for the population of Azawad," said Mahamadou Djeri Maiga, chief negotiator for the MNLA and the HCUA Tuareg umbrella group. "We hope this meeting will be the start of a definitive solution to a problem which has lasted half a century."
The government has said that if the two sides cannot come to some agreement by Monday it may occupy Kidal by force. France has so far resisted a military solution to the rebellion but its patience is wearing thin; Foreign Minister Laurent Fabius said this week a military campaign would be legitimate if talks fail.
Malian army officials, who asked not to be identified, said on Friday that French forces were holding back a military assault on Kidal.
The talks were supposed to have started on Friday but were delayed after the Malian government asked for the inclusion of representatives from the secular Arab Movement of Azawad (MAA), which opposed MNLA control of the region, and the pro-government Gandakoye black African militias.
Burkinabe mediators refused the request.
Tiebele Drame, the government's chief negotiator, told journalists at the start of the talks that a deal to hold elections was a necessary first step to resolving unrest in northern Mali.
Long-term solutions would have to wait until after the elections, since the interim government of President Dioncounda Traore lacks the political authority to make a far-reaching deal with northern armed groups.
"Once Malians choose a president who has popular legitimacy, he will then be able to start talks with armed groups for the definitive resolution of the northern crisis," he said, calling on rebel groups to lay down their arms.